The Effects of Preeclamptic Milieu on Cord Blood Derived Endothelial Colony-Forming Cells

Preeclampsia, a hypertensive disorder of pregnancy, is one of the leading causes of infant and maternal death worldwide. Despite the dangers of this disease, there is still a large gap in knowledge when it comes to the root cause. This is due primarily to the complexity of this disorder as it affects many systems in the body including renal, gastrointestinal, nervous, and cardiovascular systems. There is no uniting hypothesis on the origin of preeclampsia, however, endothelial dysfunction and angiogenic factor dysregulation are known to play a role in progression. Currently, treatment primarily focuses on fetal surveillance and mitigation of symptoms primarily through medication. However, the only definitive treatment is delivery, which can result in a premature birth. Additionally, the mother, the child, and any children born after the hypertensive pregnancy have an increased risk of cardiovascular disease, stroke, and hypertension. Therefore, treatment for mitigating cardiovascular issues is vital to improving maternal and fetal outcomes. One type of cells that can support vascularization is endothelial colony forming cells (ECFCs), a type of endothelial progenitor cells that assists in new vessel development and vessel homeostasis. ECFCs have been shown to improve other vascular associated disorders including acute kidney disease and ischemic retinopathy. Additionally, preeclampsia and other pregnancy associated disorder, such as gestational diabetes, have been shown to affect ECFC function and number. The main goal of this dissertation was to gain a better understanding of the effects of preeclampsia on ECFC function and gene expression, then to restore function to the cells. To assess the function of the preeclamptic ECFCs (PRECs), proliferation, migration, tube formation, apoptosis, and senescence were examined. It was found that the PRECs had increased proliferation and senescence compared to their healthy counterparts but had decreased tube forming ability and migration. The percentage of apoptotic cells did not change. Next, protein production and gene expression were examined to gain insight into the cause of these functional changes. It was found that Serpin E1, Fibulin 5, and c-KIT, which are angiogenesis associated, were dysregulated in PRECs. Other studies have seen similar functional changes when ECFCs are affected by gestational diabetes, some of which were caused by the dysregulation of transgelin, an actin binding protein. It was found that though the amount of transgelin was not significantly different in the ECFCs and PRECs, the preeclamptic cells had more aligned to F-Actin fibers, which can affect migration and alignment to shear stress. Additionally, transgelin 2 was examined, which has been shown to be dysregulated by preeclampsia, but had not been studied in ECFCs, and found that it is significantly increased in PRECs. The samples were flow tested alongside transforming growth factor-ß inhibitor treated PRECs (TGFßi). It was found that PRECs have significantly lower alignment to shear stress, but the TGFß inhibitor treatment restores it. Finally, small extracellular vesicles (sEVs) produced by the cells were examined. The sEVs provide a snapshot of what is happening in the cell through their cargo of RNA, DNA, and proteins. The microRNA profile of the sEVs was significantly different between the ECFCs and PRECs. When comparing the sEVs at different passages, there was no overlap between the microRNA expressed in the two groups. However, the pathways affect by these microRNA are similar. When treating the cells with the sEVs, it was found that the PREC sEVs caused the ECFCs to have decreased tube forming ability, but the ECFC sEVS improved the PRECs’ tube formation. Overall, the studies presented in this dissertation highlight changes in ECFCs during preeclampsia, both functionally and on the gene expression and protein level as well as finding potential treatments to restore some function to the cells.<p></p>